Many power toothbrushes have been proposed in the past, and a wide variety of power toothbrushes have been put on sale. Representative examples of these include types in which an attachment with a brush member on the end is fitted to a case in such a way that the attachment is free to move relative to the case and is also removable, and this attachment is driven by a motor mounted inside the case such that the attachment moves in the direction of its length, and types in which the brush member itself is driven instead of the attachment.
For example, in Japanese Patent Publication No. JP 55963/1986, there is disclosed a power toothbrush in which the brush head vibrates finely. In Japanese Patent Publication No. JP 64204/1986, there is disclosed a power toothbrush in which a toothbrush fitted to a drive shaft is driven so that it moves reciprocally either in its axial direction or perpendicular to its axial direction. In Japanese Patent Publication No. JP 79410/1986, there is disclosed a power toothbrush in which the stroke of the axial reciprocating motion of the toothbrush can be changed.
In the conventional types of power toothbrush mentioned above, in power toothbrushes in which the toothbrush is made to vibrate finely, in case the whole toothbrush is gripped firmly, the fine vibration is absorbed and the actual movement of the brush member becomes almost zero, and consequently the brushing effect is poor. In power toothbrushes in which the brush member is mounted on an attachment part (corresponding to the shape of a normal toothbrush) and the attachment part is caused to move, the brush member itself is fixed to the attachment and does not move relative to it. In the types in which the brush member itself rotates, the attachment part on which the brush member is mounted does not move.
An object of the present invention is to provide a power toothbrush having a superior brushing effect, achieved by an attachment on which a brush member is mounted, which is given a reciprocal motion in the axial direction while at the same time the brush member itself is given a rotary motion, and which has a simple construction and is of low cost.